Quadruple 20 millimeter gun mount mechanism for controlling the aiming of a gun



Dec. 19, 1950 J. M. EWART QUADRUPLE 2O MILLIMETER GUN MOUNT MECHANISM FOR CONTROLLING THE AIMING OF A GUN 8 Sheets-Sheet 1 Filed Sept. 16, 1948 Byh Dec. 19, 1951) J. M. EWART 2,534,344

QUADRUPLE 20 MILLIMETER GUN MOUNT MECHANISM FOR CONTROLLING THE AIMING OF A GUN Filed Sept. 16, 1948 -8 Sheets-Sheet 2 Dec. 19, 1950 J, Ew 2,534,344

QUADRUPLE 20 MILLIMETER GUN MOUNT MECHANISM FOR CONTROLLING THE AIMING OF A GUN Filed Sept. 16, 1948 8 Sheets-Sheet 3 Dec. 19, 1950 .1. M. EWART QUADRUPLE 2o MILLIMETER GUN MOUNT MECHANISM FOR CONTROLLING THE AIMING OF A GUN 8 Sheets-Sheet 4 Filed Sept. 16, 1948 n NA &

b Dec. 19, 1950 J, EwART 2,534,344

' QUADRUPLE 20 MILLIMETER GUN MOUNT MECHANISM FOR CONTROLLING THE AIMING OF A GUN Filed Sept. 16, 1948 8 Sheets-Sheet 5 Dec. 19, 1950 J,'M, w -r QUADRUPLE 2O MILLIMETER GUN MOUNT MECHANISM FOR CONTROLLING THE AIMING OF A GUN Filed Sept. 16, 1948 .8 Sheets-Sheet 6 Dec. 19, 1950 J. M. EWART 2,534,344

QUADRUPLE 2O MILLIMETER GUN MOUNT MECHANISM FOR CONTROLLING THE AIMING OF A sum Filed Sept. 16, 1948 8 Sheets-Sheet 7 fill/6n for John N. Ewart 10 I M 3 g i Dec. J, M, EWART QUADRUPLE 2o MILLIMETER GUN MOUNT MECHANISM FOR CONTROLLING THE AIMING OF A GUN Filed Sept. 16, 1948 8 Sheets-Sheet 8 fizz/072ml" John/ZEu/arf By hi I he Patented Dec. 19, 1950 QUADRUPLE 20 MILLIMETER GUN MOUNT MECHANISM FOR CONTROLLING THE AIMING OF A GUN John M. Ewart, Beverly, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. 5., a corporation of New Jersey Application September 16, 1948, Serial No. 49,614

1 Claim.

This invention relates to mechanism for controlling the aiming of a gun, and more particularly to means by which gun movements in azimuth and elevation may be directed from either of two control stations and, upon occasion, an operator at one of these stations may render the other control station inoperative. It will be recognized that application of the invention is not necessarily restricted to mechanism for controlling guns but may well have other uses such as, for example, in control mechanism for mounts for search lights or sound receivers.

When employing rapid-fire guns against fast moving targets, it is commonly desirable that one man of a gun team serve as gunner while a second man be in a position to assist in tracking targets, charge the guns with ammunition, or perform other miscellaneous duties. Preferably, both men should have within easy reach of their respective stations the means whereby either can assume complete control of the laying and firing mechanisms. Should the gunner become disabled, or his controls damaged or for any other reason rendered ineffective, the continuance of effective firing requires that his assistant shall immediately take over control without interference from the gunner or hinderance from his inoperative post. The assistants control grips must in these circumstances remain maneuverable even though debris prevents movement of the gunners grips or they are being wielded aimlessly.

One object of the invention, therefore, is to provide improved dual control mechanism for a gun mount such that a gun or guns supported thereon may be operated at will from either of two spaced control stations, and a gunner at either one of these stations may, in emergency, maintain maneuverability of the mount by rendering the other station inoperative. To this end, a feature of the invention resides in the provision of independently operative means by which either of the two gunners may control hydraulically powered gun movement in azimuth and elevation and either may energize a solenoid to free or disengage the mount from the others control so as, effectively to assume complete control himself.

The above and other features of the invention including novel combinations of elements and arrangement of parts will be more particularly described in connection with one embodiment, reference being had to the accompanying drawings, in which Fig. 1 is a side elevation of a quadruple gun mount (some portions being broken away) having control mechanism illustrative of the invention;

Fig. 2 is a rear elevation of a portion of the gun mount, portions of the housings being removed to show more clearly the mechanism of the spaced controls;

Fig. 3 shows a diagrammatic view in perspective of the azimuth and elevation driving mechanism, the linkages connecting said mechanism with the control grips, and the solenoid-operated mechanism;

Fig. 4 is a sectional detail view taken on the line IVIV of Fig. 1 and showing azimuth and elevation drive pumps with a portion of their control mechanism;

Fig. 5 is a plan view of the power control cam mechanism;

Fig. 6 is a View in front elevation of the mechanism shown in Fig. 5;

Fig. 7 is a detail in plan of the dither mechanism indicated in Figs. 5 and 6;

Fig. 8 is a detail, portions being broken away for clarity, showing an enlarged view in elevation of solenoid-operated mechanism;

Fig. 9 is a section on the line IXIX of Fig. 8, the frame and securing bolt being in dash lines for clarity, showing the mounting of the centering springs and levers;

Fig. 10 is an enlarged view in elevation, with parts broken away, of a control stand seen in Fig. 1;

Fig. 11 is a plan view taken along the line XI-XI of Hg. 10;

Fig. 12 is a view partly in elevation and partly in section. on an enlarged scale, of one pair of the control grips shown in Fig. 2;

Fig. 13 is a section taken on the line XlIIXIII of Fig. 12; and

Fig. 14 is a wiring diagram of the circuits pertinent to the invention.

The words right and left are hereinafter used to indicate direction respectively to the right or to the left of the gunners when they face the gun mount and are in their normal operating positions.

The illustrated gun mount comprises a circular metal base 2i! (Fig. 1) adapted to be bolted to the floor of a tank chassis or to any other movable or stationary supporting structure. Concentric with and secured to the interior of the base 2i! is a conventional azimuth fixed ring gear 22, partially indicated in Fig. 3. A circular plate 24 (Fig. 1) is mounted on the base 21! in suitable manner to allow the mount rotation through 360 in azimuth. As will hereinafter appear, the mount includes a plurality of gun assemblies, azimuth and elevation driving mechanism, and controls therefore, all supported by the plate 2G for rotation therewith.

The plate 2 serves as a platform for a-pair of spaced standardstfi (only one'of which is shown in Fig. 1) that extend upwardly, supporting in conventional manner a pair of twin gun assemblies G mounted in gun-adapterrhousings zt, and a segment gear at, the :gunsbeingadapted to be swung in unison with the gear 36 about the horizontal axis of trunnions not shown but journaled in the standards.

Near the rim of the plateZ' i and thebreeches of the guns are the control stations each being provided with a control stands?! and a gunner s shair B l. Also supported by the plate 24 and easily reached by a gunner from either enamel: is a central control housing 36 (Fig. 2) on which are mounted electrical control 'switches fili, fi and "42 for functions later tobe described. 'Tra'n'sthe driving mechanism.

The hydraulic power means for rotating the mount in train and moving the guns in elevation together with the power control linkages are shown schematically in Fig. 3. An electric-motor diagrammatically indicated in Fig. 14 may 'receive electric energy from'any suitable source,

such as a tanks generators and batteries, and drive through a shaft 48 (Fig.3)"an enclosed'g'ea-r train and shafts '49 and 59 to run an azimuth driving hydraulic pump 52 and an elevation driving hydraulic pump 54, respectively. It will be understood that a fluid reservoir (not shown) may be afilxcd to the platform 24 and'connect with the hydraulic'drive system. Fluid fiowfrom the azimuth pump 52 andelevation pump 54 is conducted by suitable pipingto anazimuth hydraulic motor 56 and an elevation hydraulic motor .58, respectively, the rates "of flow to the azimuth and elevation motors being regulated by an azimuth'control valve 68 and an elevation control valve 52.

As shown in Fig. 3 the motor '56 rotates 'the platform 2 in azimuth'by'driving'a worm 6'4 and drive gears 8'15, 88, the latter extending'downwardly through an opening'in the platform to mesh with the azimuth fixed ring -gear'22"within the .base 28. 'In similar manner the'motor 58'may .For governing the laying .of the guns,'settings of'both'the-azimuth and elevation Jpump control valves 6 and 52 may be adjusted from either :or the aforementioned control stations, the respective valves'having similar but independently "operative linkages connecting with .the control .handles-orgrips in each ofsaid stations aswill now be described. In view of the practically identical structure and operation of the right and left-hand gunners 'means for laying and firing the guns, as indicated bythe drawings, wherein identical elements bear like reference characters, it will su'fiice in this regard to restrict .theldescrip'tion tothe right'handgunners control mechanism. "The control stand32 "(FigsjL 2, 4 and 10) supports the lower portion of an elevation shaft 14 for rotation in a bearing 16, the upper portion of the shaft i4 extending into a housing I8. A horizontal member 8!}, seen in Fig. 12, extends through and is rotatably mounted .inthehousingflfito carry 'aspair of. gunners control-grips82 in 'handIe-barJfashiQn. Aifinger 84 (Fig. 10) nonrotatably secured to the member 83 .projects therefrom to straddle a cylindrical collar -86 which is slidable on the shaft Hi. The collar M is provided with three spaced annular ribs 83. vIhe-two=upper ribs form a channel in which the finger 84 holds for engagement therewith a roll "96. -A "roller 92 arranged to ride in the channel formedb the two lower ribs 88 is supported 'by one arm of a bell crank 9 3 that is ;pivotallysconnected-to the forked upper end of a pin 96. The other arm of the bell crank 94 has a ball-and socket connection with a lever 98, the latter having a similar'connection with a lever 'l til affixed' to the elevation shaft M.

-Th'e "pin 96 extends downwardly through an arcuate slot I'iJ Z (Fig. 11) in'the base -'of the housing 18, through-a flange -II2, andis"locked against 'movement ina socket mc pr'ovided in -'a fixe'dhub ififi ofthe stand-32 by a'pin M8. 'The arcuate s'lot 1 532 is concentric with the shaft M. 'The housing l-iijis according'ly permitted to turn 'about' the shaf-t "M as an' axis when-so moved by the-grips 82, and'in so rotatingfth'e housing T8 likew-ise turns an'azimuth shaft N5, the flange I I2 being integral with 'said sh-aft and screwed to the base of th'ehous'ing W8 (Fig. 12'). The azimuth shaft tlfi concentrically surrounds the'ele vation Shaft "M -'but is rotatable independently th'ereof, being supported' ina bearing I' I 4 formed in the hub H36 and aball bearing 5 H6 mounted in 'alowerportionof the housing ArmsfI I8 "and "I 20 (Fig '3) affixed respectively -'-to the shafts III: and "M are-pivotally connected res'pectively,"by'means of links I 22 -and I-Z L'to the locking-arms I26and I 23 of "disconnectingmechariismfli'ig'sfi an'd 9) nowto' be describe'd. Beneath each 'gunners chair and within the 'housing 461s the solenoid-actuated means by which "the'grip controls 82 -may'-be-operatively disconne'cted from the above-mentioned azimuth-and elevati'on valves 60 and B2 *whiletheother gu'nners grips 82 are effectively locked to their-linkages for independently "controlling these valves. 'A'fra'meI3B (Figs. 438- and 9)-secured to the plate 24 supports a solenoid I32 having a stem afiixe'd to an-armof-a bell-crank lc lpivotally mounted on the frame 36' to'ope'rate a slide lever I 36 journaled-therein. A verti'cal fulcrum stud I38 having a shoulder -I3l (Fig. 8) is-secured "by a bolt I39"tohorizontal'portions of theframe andpasses throug'ha slot in abloc'k I 40 which is integral with the'leve'r [36. "concentricallyarranged'for pivotal movementaboutthe stud I 38' arethe hubs of-com'p'osite bell cranks which respectively comprise-control levers I42, I4 and the cooperating locking arms I26, I28. Telescopically mounted ifor end-w-ise projection from .a horizontal'bore I :16 'in each .of the locking arms 2 6, I28 are spring-pressed, hollow or .thimble-like plunger-s I48, I50 respectively. Stop pin I52, I54 afiixedzat .right angles to the respective plungers M8, .156 {project toward eachother through oppositely-dis- '70-posed slots I55,-I5 6 in-thelocking arms .Ii t, I28

anclare normally engaged by the arcuateperimeter-oftheblock MI} thoughthe composite bell cranks may be'disposed at different angles about the stud I38. The slots I56 define the extent'to whihtheplungers maybe displaced'in one direc- .the lower centering levers.

Hid consequently acts yieldingly to maintain ention in the bores I46 by the block I40. The displacement thus allowed is adequate for unseating the conical detent portions of the plungers from matching holes in the respective hubs of the control levers Hi2, Md and then the locking arms I25, I28 are free to swing about the stud I38 independently of the control levers Hi2, I44 respectively. When in their locked or operative positions the plungers hold the locking arms of the composite bell cranks in fixed angular relation to the corresponding control levers.

Also mounted for pivotal movement about the stud I38 for purposes hereinafter explained is a pair of oppositely disposed upper centering levers I58 (Fig. 9) and a pair of similar lower levers I69 (Fig. 8). Upper and lower pairs of centering tension springs I62, Hid, respectively, extend from projections on the frame I323 to oppositely disposed ears on the levers I58, I60. Stop lugs I63, I93 are secured to the locking arms I26, I28,

respectively, stationary lugs E55 are ailixed to the frame @559 to enable the springs always to return the levers I58, I69 to what may be considered their central or neutral positions. The arrangement is such that a lug use and a lug I65 extend between and are engageable with the upper centering levers, and likewise lower lugs i 33 and I65 extend between and are engageable with Each spring I62 or gagement of a centering lever IE3 or IE with a pivotal stop lug 593 when a locking arm is swung, and accordingly the arm is always under tension to return to its central or neutral position. Thus it will be seen that the composite bell cranks always tend to resume their neutral positions when permitted to do so by the control grips 82 and, if the locking arms are not acting as a part of these bell cranks because their plungers is, 56 are unseated, these arms still resume neutral positions wherein the composite bell cranks may again be formed.

An azimuth rod I68 is connected to the upper ccntrol levers Hi2 and an elevation rod 186 is connected to the lower control levers Idfi of the two disconnecting mechanisms. Within the motor drive housing 44 (Fig. 4) is a dual series of independently movable links which effectively transmit control movements of the azimuth rod I68 and the elevation rod ifit to the azimuth control valve 59 and the elevation control valve 62, respectively. Since the structure and arrangement (Figs. 3, i, 5 and 6) for opening or closing the valve 62 corresponds to that provided for adjusting settings of the azimuth valve 60, only the latter will now be described. A reciprocable azimuth valve stem iii! (Figs. 5 and 7) is connected by pivot pins to one end of a lever Il'2 by a link I'M. The lever I12 (Fig. '7) is fulcrumed on a movable vertical pivot pin H6 and has a yoke end adapted to be engaged by an eccentric H8. The latter is one of two cams rotatably driven by a dither drive shaft ass (Figs. 3, 5 and 6) continuously powered by the motor drive gear train. The lever H2 is thus caused to oscillate with an amplitude that is insuificient to disturb desired settings of the azimuth valve but renders it promptly responsive to azimuth control movements which may be transmitted by either set of control grips 82 via the azimuth rod M58 as will be seen. A housing I82 for the dither mechanism supports a bracket I83 holding a stationary pivot stud 38 3- (Fig. 5) on which a bell crank I86 is mounted, one arm of the crank having an end holding the pivot pin I16 and a longer arm extending to support a cam roll I88. The latter engages a curved cam slot I90 in an arm of a bell crank I92, the slot being formed to secure movements of the valve stem I10 in accordance with azimuth movements of the control grips. The bell crank I92 is pivoted at I94 to the platform 24 and has a lower arm I95 which is pivotally connected to the azimuth rod I58. A corresponding arm of the bell crank for transmitting elevation control movements to the elevation valve is similarly connected to the elevation rod IE6.

As hereinafter described, elevation stop mechanism in the not unusual arrangement shown in Fig. 1 is used to prevent either gunner from elevating the guns more or less than desired limits. The range of these limits is represented by the distance spacing two stop screws 200 afiixed to the right hand segment gear 30 (Fig. 1), and an intermediate stop lever 202 is fulcrumed upon a gun adapter housing 28. The lever 202 is in a position to be contacted by either of the screws 209 and is pivotally connected to a turnbuckle rod 204. An end of the latter is received by a crank 206 carrying a bevel gear arranged to mesh with a gear 208, the turning of which moves a slotted link 2I0 (Figs. 3 and 4). A stop stud 2 I2 secured to an elevation bell crank 2M (corresponding to the bell crank I92 in the azimuth linkage) is slidable in the slot of the link 2I0. The arresting movement of the guns by one of the stop screws 290 pivotally moving the lever 202 slides the link 2I9 to shut off the elevating power as will be seen hereinafter and this action is accompanied by the operation of simple shock absorbing mechanism now to be described. A projection of the lever 202 (Fig. l) is engageable with a piston rod 2l6 mounted in a cylinder 2I8 supported by the housing 32. The cylinder 2I8 encloses two springs (not shown) oppositely engageable with a piston on the rod 2I6 and they thereby yieldingly hold said piston in a position intermediate the length of the cylinder 2I8.

The firing mechanism for each gunners station includes a fire treadle 220 (Fig. l) and a right and left-hand finger trigger 222 (Fig. 13), the triggers being arranged to actuate microswitches 224 (Fig. 12) in the control grips 282. Conveniently, each grip also has an action lever 226 (Fig. '11), slight hand pressure on one of which is adequate to close a micro-switch 228 and thus commence operation of an electric motor for driving both the azimuth and elevation hydraulic pumps 52, 54. Referring to Figs. 2 and 13, the toggle switch 38 is the main switch controlling electrical energy from the source of supply and the switch 40 is a safety to be closed only when the gun mount is to be operated. The switch 42 when thrown to the right activates the right hand gunners control grips 82 and energizes the solenoid I32 under the left-hand gunners chair. If the control switch 42 be thrown to the left, the left-hand gunners grips are activated or made alive and the other solenoid I32 beneath the right-hand gunners chair is energized. A suitable motor relay 230 and a firing solenoid relay 232 are included as indicated in Fig. 14.

In operating the gunmount, switches 38 and 40 having been closed, a gunner may assume control of firing and laying the guns from his station by throwing the switch 42 toward himself. He fires the guns by depressing treadle 220 01 a trigger 222. He controls azimuth movement of the mount by rotating his grips horizontally to the right or left of a neutral position which corresponds to a closed position for the azimuth ewes- :344

7 valve 60; and '1' effects elevation :or .depression :zof the gunstoth'eidesired extent by raising or lowering 1 the :control :grips 8.2 from aineutral .position corresponding to the :closedlpositicn of the elevati'on valve 62. It will be 'seen thatthisazirnuth control movement .turns the housing 18 (Fig; 10) and with it the azimuth shaft I I0 therebyrpivotally 'moving the locking "arm ['2 6 andthe control lever 142 as a 'unitor bell crank to shift the azimuth rod 1-68. Similarly,'-it will'bevseen his elevation control "movement of the -grips '82 1'0- tates .the :elevation shaft 14, athe'scollar -86 fleeing raised :or lowered thereon by the .grips to pivot the crank 94 and --thus:rotatabl-y shift the bell crank MN]. As the-shaft M-is turned withdts lever 1 l 2'0, the lower locking arm 128 :and control lever I'M are thereby :pivotally movedaasa :unit to shift theelevation rod 166. Shifting 0f the rods 1-68, it, "which is accomplished by imaneuvering the; grips at either of thecontrol sta- .tions, effects: guncontrol hydraulically in azimuth and in elevation by setting the azimuth and elevation valves- 60,- 62 respectively. Each of the valves is changed in its :"setting by vthe :above described link-age which extends from the: respective valvestems via the bell crank 1'86 andthe cam slot|9'0 to=its actuating rod LBS-or 1-68. The movingof a control-grip! 82in any direction from neutral -is accordingly translated into azimuth and elevation valve settings allowing .rates of pressure 'fluid flow to operate the azimuth and. elevation drive motors :56 :and :58 ."respectively, thus laying the "guns. Fluid flow and,:conse- ,quently, gun aiming will be at a more? rapid rate whenla grip is rotated further from its neutral position. -When the control :grip is returned, either -manuallyor upon release, to its neutral .position the valves are closed and fluid flow ceases. By reason of the above-describeddithering -mechanism which overcomes static friction load on the 'valve'stems. and because'of thalack of lost motionrin the linkages moved bythe control grips 82, a reversal in-thedirection of i'grip movement immediately obtains a resetting. ofthe azimuth and elevation valves and corresponding change indirection of the :fluid flow driving the hydraulic motors 56, 58.

Operation of :the gunners controls as just related assumes the solenoid actuated discon--.

-nesting "mechanism under his chair :has ;.per-

If occasion sarises .llhGztVIO-VVQY-triple-p013 selector switchfiliitoward himself thereby disrupting the aother .gunner s :controls F and efiectively cconnecting his own with "the -firing mechanism and the valves 15KB, 62.

Upon s'o :throwing :the switch 42, the assistant energizes the solenoid 5132 ;under the gun'ners 'chair and "deenergizes the :solenoid J32 :under .his :own I chair. :slide the adjacent block M0 :against'both stop pins 1:52, 154 so as to unlock "the plungers 4 58,

The energized solenoid acts t'o I56 simultaneously from their respective seats and thereafter movement of the gunneris grips isinefiective for firing or transmission of =control movements to the levers 1'42, 144 and on to "the valves. The deenergizedsolenoid, however, permits its adjacent block I4 9 to he returned to normal position with the adjoining spring plungers M8, -I 5fi,2the latter again locking with the-controllevers M2, 144 for Ltransmission of control :movements direc"ted by zthe assistant. "important ifeature @to be linoted is :tnat :-:in ;both disconnecting mechanisms when ;hands are "taken off the :control {grips -8.2 the springs EH52, --i 64 which are tension'ed during sgrip movements to the right :or left :of neutral, will coactvwith ;the:centering levers 4'58, 168 13036-- 'lllll'n'it'he "locking arms 126, 1'28 and connecting control .igrips 82 to a neutral 1 or power-shutso'ff aposition. @On aimingzhis iguns vuponaa target, ;the gunner l'may irelease 'athe action levers 9-226 :from contact with a microswitch-i-ZBeso 'ithatfluidi flow to the driving -motor .is stopped and the guns :will mot doedriven :heyond "the :desired :fposi-tion in either azimuth ior zelevation.

:As the 'uns approach limitsiof elevation .or depression undershydraulic power oneofthe stop "screws J56 will engage the lever 202 causing it to shift ithe rod 254 #and thereby lturn (the crank 286. ZRotary moverheht of the latter-transmitted through the-ge'ar illii slides the slotted'linki Ill. When the stop stud 2L2 is engaged by an end-of the s'i'ot "in "the-link 2 the 'bell crank 2M -is "forcibly pivoted -to move the linkage "connecting "with the elevation valve -'-s'tem. "On reaching maximum gun elevation-the arrangement issuch that this "stem is -moved forwardly to close the valve *S'Landthe control grips 8'2 withconnecting linkage will be "automaticallyiorced to return to their corresponding neutral position "for elevation. *When maximum depression of the guns'is tabout to be reached the elevation "valve 'stem will "be "forcibly "retracted to its neutral "position inthe pump "54 bythe othel en'd of the slot in the .1ink2'l 0 and again'the "elevation Icon- ,trolllin'kage will return the ,grips '82 to corresponding .neutral ,position for elevation. By .means of the cylinder 21B and its springs "for centering .the 1 piston renclosed therein, the piston rod 521-6 is yie1ding1y:displaced as the "lever 2.92 .islengajged byeitherof-thelimit screWs'ZOil. Accordingly, the shock of braking thenmount-dur- 'ing elevation is somewhat absorbed, "a less sudden thrustis transmitted .to -.the linkilllpano'l the action of the springs-in tending *to-recenter "the Episton is .an aid -to the :gunner when he manipulates "his control grips so as :to reopen the:ielevation valve 6'2 for withdrawing thegguns from their extreme positions :of elevation or idepression.

Having :thus described v1 my invention, what I claim as new and desire to secure by Letters "Patent of --the United States is:

"In a gun -mount including hydraulic motors 'for'training a gun-on themount'in azimuth and elevation, valves for controlling "said motors, "a control 'standlocateol on "each side o'f'said gun and spaced therefrom, a .control panel located on saidmou'nt and accessiblefr'om either c'o'ntrolstand aset of controlgrips on ea'ch'con- 'trol stand, mechanical connections including horizontally extending rods leading irom said grip tosaid valves, saidconnection including azdisconnecting. mechanism for each set of grips, eachdisconnecting mechanism including 1 a 'pair .of bell cranks normally-having theirrespective arms locked for-azimuth and elevation control -movements about a common fulcrum, 1 means for simultaneously unlocking the arms of one esaidlpairs 16f :bell :cranks :a solenoid opera tively :connecterl to eachnisconnecting mechanism for actuating said means and a switch on saidcon- 'trol panel foncontrdlling said solenoids whereby an 'operator at either of said control stands i may JOHN M. EWART.

REFERENCES CITED The following references are of record in the file of this patent:

Number 10 UNITED STATES PATENTS Name Date Meigs et a1 Oct. 12, 1915 Akemann Apr. 19, 1921 Hewlett et a1. Jan. 17, 1933 Davis Aug. 27, 1946 Hull et a1 Sept. 24, 1946 Chase et a1. Oct. 5, 1948 Knowlton Dec. 28, 1948 Gross Nov. 1, 1949 Duplessis Dec. 20, 1949 

